<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>圣杯</title>
    <style>
        .box{
            width: 80%;
            background-color: pink;
            margin: 100px auto;
            height: 60px;
            display: flex;
        }
        .one,.two,.three{
            height: 60px;
        }
        .one,.three{
            width: 60px;
        }
        .one{
            background-color: red;
        }
        .three{
            background-color: green;
        }
        .two{
            flex:1;
            background-color: skyblue;
        }
    </style>
</head>
<body>
    <div class="box">
        <div class="one">1</div>
        <div class="two">2</div>
        <div class="three">3</div>
    </div>
</body>
</html>